The AM Forum

Didn't want to hijack K1JJ on his topic in the QSO section on his pileup recording. Thanks guys for the info on the Beverages and K9AY antennas.   I read about a two wire beverage that does not need a termination for a single direction.     At the fed end it uses the standard impedance transformer and at the other end it uses some sort of termination transformer.    I was wondering if any of the 75M Dxers use or know anything about this?    Apparently you can switch directions but only have to feed it at one end.    How do you think a 400 ft beverage would be on 75M compared to the K9AY loop.     I thought I knew a lot about antennas, but I never heard of the K9AY loop or the two wire beverage.

I have a beverage that is unterminated that works pretty good  It has about 15 db reject on the sides but is bidirectional.  I think the 2 wire thing you are talking about can be bought from DX Engineering.  I had a friend that had a switchable beverage that had a box at the feedpoint and one inside at the receiver.  I don't know the particulars.  I do know it could be switched from one direction to another 180 degrees opposite from the inside.


I have also played with a K9AY loop and it works very well.  According to Gary/W7FG it gave him up to 25 db rejection.  The nice thing about it is that you can switch it in any direction rather than be fixed to just two directions.  It takes up a lot less space and is easy to put up.  The only downside is you have to have a control cable from your operating position to the base.

But you have to switch the other as well, I just don't remember how it works.  I think it switches over the feedline.

The "basic"version of the K9AY does not need a control cable. All the switching voltages are fed over the coax.

I thought the two wire bev still needed to be terminated. If not cool. Even if it does, it's nothing more than a 470 Ohm, 2 watt, noninductive resistor and a ground rod, same as any other bev.

I will run some models of a 400 foot bev and a K9AY to see how they compare. Remember that there are preferered lengths for beverage where they exhibit the best front-to-back and front-to-side ratios. The preferred lengths for 80 meters are roughly (it varies some with height and ground conductivity), 150, 295 Feet, 440, and 580 feet. The latter two lengths are superior as the take-off angle is lower and the front lobes are more narrow. The 150 footer probably would not be a good as a K9AY. The 295 footer would roughly compare to a K9AY, but I'll say more on that after running some models. 

Bob,

Thought I'd transfer these Beverage antenna plots over here since you started a new FB receiving thread... :-)

BTW, Steve sent me a good article on phased K9AY loops. Quite an interesting read. I'd try the four square or Bobtail versions if I didn't already have Bevs up here.  Here it is:

http://www.aytechnologies.com/TechData/K9AYLoopArrays.pdf


T

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For anyone interested, here's the horizontal and vertical patterns of a single 600' beverage compared to a pair side by side, spaced 180' apart.  Both are 7' above the ground and terminated.

The red plot is the pair of Bevs (fed in phase) and the black is the single Bev.  Notice how the pair has less side lobes, thus less noise off the sides. The horizontal pattern roll-off of the pair is much sharper, (narrower) though the vertical pattern stays the same since we are only stacking horizontally. The take-off angle is about 25 degrees, almost perfect for low angle DX on 75M.  These would make great receiving antennas for coast to coast AM work as well.

Notice these radiation patterns look as good as any 6 element Yagi at 1/2 wavelength above ground.   Beverages are tremendous receiving antennas for the low bands considering what it would cost in time and money to put up its transmitting counterpart.

Thanks to Steve/HUZ for making these models available.

T

The beverage is effective, but I wonder if it would be worth the real estate, cost and effort to put up the phased array.  According to the chart, the difference between the two is only between 6 and 10 dB, whether absolute signal strength or f/b ratio.

Hi Don,

Well, when it comes down to performance, it's just like getting the last few tenths of a second out of a quarter mile dragster. Likewise, squeezing the last edge out of a receiving system soon reaches diminishing returns.

However, 6db is a tremendous difference in the real world if you're near the noise level trying to pull out a signal. 

But forward gain means little with Bevs - the real advantage is the difference between the sharpness of the patterns.  If you look carefully at the horizontal  db vs degrees grid, you'll see the two phased Bevs frontal pattern falls off about TWICE as fast as the single Bev.  What this means is the atmospheric noise coming from the areas not desired is rolled off faster too. The side lobes are also smaller, thus the noise off the sides is reduced. All this reduction in accumulative noise adds up, but will vary depending on what's happening in the sky... :-)   S/N is improved.  The pattern comparison is about the difference between a 3 element and a  ~6el Yagi.


This assumes you want a narrower pattern. But the path to Europe is far enuff away and the Euro population concentration falls between a narrow range, between about 30-60 degrees heading from CT, so a pair of phased Bevs from the east coast or farther west USA work out very FB!

For example, there are nights when I can switch to my Yagi beaming SE and hear high levels of pure atmospheric noise and static. (or T-storms)  The phased Bevs have a nice null in that side direction.... better than the single Bev.  With the phased Bevs on, I hear little noise from the SE and the NE Euro signals pop right up nicely.

As a hands-on experience, I've noticed the comparison of the 2el NE quad vs: the Bevs over time in dual diversity. When I had only ONE Bev, the quad usually had a slightly better S/N on receive. Now using the phased Bevs, it's about equal most nights. The NE signals will favor one or the other variably, as they did the other night into Eur.

So, in summary, yes, it was worth the extra trouble for me.  Besides, if I knew I could try it and didn't, it would bother me until I did... :-)

Hope this helps.

T

 

Gain is irrelevant here and it is for most receiving antennas. It's directivity. The phased array is far more directive and thus makes a better receiving antenna, at least in the desired direction. It's better to look at things like RDF (receiving directivity factor) when comparing receive antennas.

Ultimately, whether it's worth it depends on your goals and the amount of time/money you want to spend. Some guys phase 3 and 4 beverages, and put up multiple versions of these arrays up to cover many directions. But they want the max directivity in numerous directions to cover all the DX paths. For more general receiving purposes, a single beverage may be good enough. For some people, a dipole is good enough. It all depends on what you want.

However, I would recommend almost anyone to try one of the specialized receive antennas. You don't know what you are missing until you try it. I put up the K9AY for DX work. It does well at that. But it also helps out on many much shorter distance AM contacts, especially on 160 meters. I'd never have even guessed, let alone known this, if I hadn't actually built the thing and tried it.

From the modeling, the 400 foot Beverage is superior to the K9AY. Look at the plots below.

The elevation take-off angle (TO) is 30 degrees for the Beverage and 35 for the K9AY. For DX, the lower take-off angle is better. If you are looking to improve the SNR on shorter range paths (like stateside AM), the higher TO may be better. Also notice on the elevation plots that the pattern is sharper for the Beverage. The output on the backside drops off more quickly. Yes, it has some lobes on the backside, but even those lobes are less the the more smooth pattern of the K9AY. And the big notches on the Beverage mean even less noise or QRM coming in from the undesired direction compared to the K9AY.

Continued in the next post ....

... continued...

Looking at the azimuth patterns, again the Beverage is much sharper - the beamwidth is less. This also means less noise and QRM.  The  downside is that you need to point it more precisely in the desired direction.  It also means you will cover less area on the globe than with the K9AY, but what you do cover (and it is a significant chunk), you will cover far better.

So, for the one desired direction, the Beverage is better than the K9AY. However, the K9AY can easily give you four directions. So, depending on your requirements, the K9AY may be the better choice. But, if you want to cover Europe, the Middle East and Northern Africa from your location, the beverage is the far better choice. If you make it a two-wire reversible Beverage, then you can also cover some the the Pacific, including VK and ZL land. Take a look at a azimuthal-equidistant projection map centered on your location. You can quickly see what headings your need to cover the desired parts of the globe. You can generate this type of map at the link below.


http://www.wm7d.net/azproj.shtml

Steve,

Yes, a HUGE difference in my eyes, in favor of the Bev - if you're looking for raw performance.  Good job, OM. 

A 400' Bev is still of reasonable length, considering the nice pattern.  There was a time in the 80's when I had up a 2,000' long Bev when I didn't know any better. That was even too long for 160M.


Another point... I realize it's in a delta config, but since the K9AY is fed against ground and stands up in a "vertical" manner, I wonder if it is more "local noise" prone than the horizontal beverage?  The Bev is also fed against ground but is physically more horizontal.

I've never tried a K9AY, so have not compared it. Maybe when you get your Bev working you can, assuming you have some local noise. (hope not... :-))

T

The answer is yes. The K9AY is essentially two short phased verticals. It is more sensitive to local man made noise. Luckily, I have very little here. If you lived in a noisy urban location, I'd use shielded/balanced loops for something small. If space was available, yes the Beverage would be better.

Some pix of the K9AY at HUZ Radio.

http://www.amwindow.org/misc/lakehouse/antennas.htm

My beverage is 900' in winter, but I have to shorten it to 390' in summer to stay out of the way of the farmer who leases the crop land.  40m performance drops off when I lengthen it, but 80 and 160 performance improve.

The beverage is highly vulnerable to local electrical noise, particularly if it happens to originate from the direction of the main lobe, since it responds mostly to vertically polarised signals.  Narrowing the lobe will make the antenna seem quieter because you are closing the window on random noise sources. My problem is that the chronically noisy power line runs east to west, and is located about 1/3 mile north of here.  Whenever it acts up, no matter where the actual source of the noise is located along the line, it would pretty well render the beverage useless even if I could rotate the whole thing over an angle of 150° or more.

It makes a tremendous improvement over the 110' high 80m dipole when receiving signals from northeast USA or Europe.  Usually I hear signals from N.E. USA very poorly on 160 with the vertical.  The indoor rotatable loop is a little better, but nothing like the beverage when the noise is quiet.  Probably, for my purposes, the single wire is better, since the AM signals I hear arriving from the "northeast" cover a fairly broad sector of the azimuth.  If I had more of my real estate available for antenna use, I am sure a multiple wire array would be a big improvement for Europe, but all of Europe from here takes in a considerable swath of angle to cover every thing from Scandinavia and northern Russia to the Mediterranean.

I believe the lobes can be made more narrow by increasing the spacing between the antennas in a multi-array.

Don,

NOT an antenna modeler here, but am contemplating a new antenna system here at the new QTH in Colorado Springs.  As I like to DX on the BCB, a bev seems to be in the future.

My question is this:  Would it take to capacitive 'loading' to shorten it for other bands?  Or would any type of 'loading' screw with the pattern?  I've never used a bev, but they seem to be the ticket for low band performance.

Thanks, in advance.

--Shane

You can add a cap or inductor to the resisitive load to change things. I plan to use an inductor on my short beverage. From the modeling, it looks like the inductor improves the F/B quite a bit. The downside is that the Beverage will be a single band antenna. On the BC band, you may have to change the cap or inductor value as you tune across the band.

I was actually thinking of a motor driven...  Best of all worlds, if it worked.

Tuning would be slightly tricky, but I think just "tune for the peak" would work best.

Since it's not a tx antenna, no problems with super sky high voltages, a bread slicer would work I would think.....  Or would a VV be better for higher Q?

I wonder if a cap and long antenna, or some L with a short antenna would be better? 

And if the cap is a good method, a VV would provide some SERIOUS adjustment capabilities! :)

--Shane

But would a capacitively or inductively loaded long wire low to the ground still be a beverage?  The latter works on the travelling wave principle, not as a resonant piece of wire, and a terminated beverage is by definition an untuned antenna.  I suspect with the L or C loading, which makes it frequency sensitive, causes it function more like a long skinny tuned  loop,  with the ground serving as the bottom side of the rectangle, combined with any phased vertical action at the up and down leads at the ends of the wire. Or maybe it just acts as a plain longwire antenna.

But if the antenna works, I suppose what you call it is just a matter of semantics.

Don,

The question you raise is EXACTLY why I was hoping to get it modeled, or to have someone smah-tah than I to do some interjecting.

I have MANNA-GAL, and it's great, but I am by NO means an antenna modeler....  However, I think I'll have a shot at it, and see what it says.

Amazing, what we can do with simple computers, I tell ya! 

--Shane

The Beverage is a section of transmission line (single line over ground plane)terminated in its characteristic impedance.  The ground plane is lossy and so the resulting radiation pattern, as opposed to a perfect ground plane/transmission line and no radiation coupled in or out.

I've modeled a short (200 foot long on 80 meters) Beverage with just a resistive termination and then with the resistor and an inductor. The right selection of inductance improves the F/B. Yes, the Beverage will now be a single band antenna, unless the inductance is changed or removed. It doesn't matter in my application. The 200 feet would be far too short to do any good on 160 meters, inductor or not. If I want to use it on 40 meters, I can just short out the inductor. I will post the modeling results later to illustrate.

And yes, as far as I can tell, it's still a Beverage. You aren't necessarily resonating the antenna with the inductance. I just set the inductance for the best F/B. I don't know if it's resonant or not. You can read an FCC memo from 1958 on the Beverage. It's all there, single wire, two wire unidirectional, two-wire switch able directions, and using reactive terminations to steer or change the nulls on the back side.

http://www.ae5d.com/bev/bev2.html


I'd go with the longer Beverage over the shorter one. It will provide more output/gain, have better directivity and have a lower take-off angle. You wouldn't need a VV for your Beverage. It's not a high Q system. A trimmer cap would work. But if you are just after making the thing look shorter for higher frequencies you may not need to mess with a cap. Depending on the range you wish to cover, one proper length can work quite well. There are numerous published lengths that cover 160 and 80 or 80 and 40 meters. If you want to optimize over a greater range than these, just use a relay to add and subtract additional lengths. It would probably be easier than trying to remotely "tune" or optimize the thing with a variable cap.

Thanks for that link.  Loads of information there plus all the embedded links in the document.  Hours of reading.  Plenty of bookmarking and copying to do.

See plots below. The null off the back is much greater with the 200 foot beverage terminated with a resistor and an inductor.

SHE"S A WIDE BODY.....Ought to work OK

The K9AY is even wider on the front lobe  - 130 degrees at the 3 dB points compared to about 90 degrees for the Beverage , so I'm hoping to see some improvement with the Beverage.

I'm still trying to figure how I can add some more wire to the Beverage (think neighbor's yard).  ;)

This is a wealth of information, thanks to all of you.   I was wondering what is the basis for the favored lengths of the beverage, I suppose it is the pattern only.    Will one that is 295 ft be better than 400 ft?    Also how well would these work during the day for the average AM contact?     Being in Central PA, I do a lot of daytime 75M listening.    Many times there is a QSO in Ohio and New England going on at the same time on the same frequency.     With the high angle at these distances, and from Steve's plots, it seems that the K9AY loop may a better directional receive antenna for daytime use.

The preferred lengths produce sharper nulls off the back/better or better F/B and F/S ratios. If you have room for 400 feet, go with it or the 440 foot length. It will be superior to the 295 foot length.

For relatively short distance AM use, I'd go with the K9AY. It has much greater high angle response, as you noted. And you can switch it in four directions. From my location in southeastern Virginia (about 60-70 miles from the NC border), I can easily hear 1-land AM stations, even those in Maine during the day, at least during the winter months. In December, I could hear these stations as early as 1300 local time. But that was only on the K9AY. With the dipole, many stations were in the noise. I don't see much improvement on most AM signals at night, except for longer distance ones, like the Midwest and West coast.

The K9AY also makes a difference on many AM signals on 160 meters at night, much more than on 80/75 meters. Even stations as close as 300 miles are often heard better on the K9AY.

Since the K9AY is so small, you could probably put both it and the Beverage up. Point the Beverage towards Europe for DX and use the K9AY for everything else. You would have it all!

Steve, do tree trunks ruin the pattern on either of these antennas.     The only place I have is full of tall pine trees,  the type that has about 80 ft of trunk with the rest of the tree up high.    One of them ought to be a good center support for the K9AY type.    I was thinking of putting up a simple terminated one for 75M aimed NE.   That would be good for the New England and east coast AM'ers in the day and the SSB DX window at night.    I don't have much for 160M to transmit and just PW on the power for 160M.

Steve, you posted some good info on beverage construction.

How about some links to K9AY construction info.  I haven't done a search lately, but in the past, most of  my searches took me to discussion forums about K9AY loops, but I couldn't find much on construction details.

I built a non-directional low-noise horizontal loop per the K6STI article in Sept 95 QST, but the results were disappointing.  It is supposed to be insensitive to ground wave signals but respond  well to sky waves, and he even published computer modelling data to demonstrate, but mine never worked any better than a random length piece of wire tossed out the shack window.

Isn't it supposed to be relatively easy to construct the K9AY so that it uses a single pole, and configure it so that it can be physically rotated by hand to null out noise or local QRM, kind of like manoeuvring the sail on a sail boat?

I notice the same thing in the day when signals are at least 300 miles away.  The optimum angle during the day on 75M is usually LOW cuz of the absorption.  I find the Tron (300 miles away) is usually MUCH louder on the high NE quads during the day. When he uses his wire array also, we can talk at 1PM, no problem. But when we each use a low dipole, it's very noisy.  However, at night, the difference is small and even sometimes in favor of the dipoles cuz the optimum vertical angle is much higher between us at night.



BTW, Bob, the trees won't bother your 75M antennas. I know guys with full blown 4-squares made of wire hanging from trees in the woods and they are some of the best ears and loudest into Europe. My bevs run thru the woods and work really FB as well as many thousands of others around the world.

However, on 6 meters I have done some tests while tuning Yagis. When I suspend a Yagi from a tree limb to tune to 1:1, I can rotate it so that the elements are within a few inches of leaves and tree branches - the swr will move up to over 2:1 or more. So there is a limit in frequency - maybe 28 mhz or so when foliage can have a meaningful effect.

I was told to be above the tree forest when beaming on 6M, or expect attenuation. Since then I always place my lowest Yagi in a 6 meters stack at least 70' high to clear any trees in the area.

T

Tom,

To add to your comments....  I understand some guys have said that their Bevs worked poorly when run over highly conductive ground like swamp land.  I would be interested in seeing the relative patterns of a Beverage over standard rocky soil (like here) and over something like super good soil OR even over ocean salt water.  That shud shed light on this idea even more.

I would model it myself, but my old MiniNec DOS program from the 80's is good only for wire arrays and Yagis, and does poorly over ground dependant systems. I would also lose hundreds of old antenna models I've developed over the years by using the  new format... sigh   (But I really need to upgrade it... :-))

T

Give mmana-gal a shot.  It's somewhat freeware, does a GREAT job, and has NEC plugins.

Again, You'd not so much lose your old stuff, but would be starting over from scratch.

I've used it on Win XP 32 bit as well as X64 Vista.  No problems, and comes with a WEALTH of "off the shelf" antennas in it's library..  Both commercial and 'homebrew'.

I even found quite a few beverages on it, just need to figure out how to add the loading constants into it..  It WILL accept loading coils, I just haven't figured out HOW to model them myself.

Not in any way shape or form affiliated with them, just a happy freeware customer (they  also make a commercial version that's supposed to be more accurate, etc....  It pretty much matches what I've seen other places for accuracy, though).

I even figured out how to GRAPHICALLY enter antennas, makes things LOADS easier than having to graph paper it out (which is why I DON'T antenna model on NEC style proggies).

--Shane

Anyone have any experience with phased loops or with the (expensive) DX Engineering phaser?

I use a small tuned loop to squash the big noise from somewhere.  It makes a huge difference, a night and day difference.  I aim the loop null at the noise and get a huge S/N difference.  I forgot the dB difference but it's amazing.

I'm pondering two of these phased.  Anyone doing that?

I agree with K1JJ on the effect of trees on low band antennas...I live in the tall trees and my experience is that the RF doesn't even "know or see" those trees until around 10 megs...My advice (from my experience) on beverage antennas is to put up whatever length you can, even if it is only as short as 60 ft...because in some situations it WILL receive better than your tx antenna...

As Tom said, no. Trees won't be a problem. Remember, you only need a 25-30 foot high support for the K9AY. You could run a a rope from any tree to the ground at the right angle and get the 25 foot support. Or a single pole made of PVC or other light mast material. The loop can make up part of the guy assembly, if needed.

Attached is the original article by Gary Breed.

I wouldn't bet on the PVC...  Nuke it in the microwave first.

I learned the hard way at 1750 meters, PVC DOES interact with RF.

If it warms in the nuke, it will interact.

I seem to remember it was pigment / dye specific, not MFG...  Some colors where worse than others.

--Shane

Remember, this is a receive antenna, so I don't think PVC would be a problem. And it's a center mast, the antenna only comes near it at one point. Also, years ago, I built a small receiving loop (about 3-4 feet across) using PVC as the spreaders and it worked FB.

The 4th Edition of ON4UN's Low Band Dxing book has extensive details on just about any receiving antenna that has been described in print.

The problem with phased Beverages is that they are monobanders wheras I find the single wire usefull thru 30M and have even used on 20M when snow static wiped out a DXpedition.

With 7 Beverages covering the compass I find that I can hear just fine, its the other end that often cant. Especially if he is in the tropics or in a building in downtown Hong Kong.

Its really hard to take a computer model and compare to real world performance with a Beverage (and many other antennas). A Beverage works best with a poor ground and is a dud over salt marshes, just ask W1KM and others who have tried them. When I operate from our cottage on the Maine coast a rotatable shielded loop is used. At home Im on top of a granite rock pile hilltop that slopes off nicely in all directions; its a location that has proven to work from 160 to microwaves.

The only help there is 10dB+ in the TX department at my end but I dont think 12KW is the way to go. Im already maxed out in antenna gain.

As far as angles are concerned it always helps to have low and high available. Ive worked some of my longest haul DX on 160 at this QTH using an inverted vee with the apex at 50'. I won a 160M contest in the late 80's at another QTH with the xcvr feeding 2 amps with one feeding a vertical and the other a horizontal at 120'. Earlier testing on SSB reported a stronger and steadier signal to W6/7 and Europe as well as full coverage closer in.

Carl
KM1H

To some extent, but it's done all the time. It largely depends on the quality of the model and the power of the modeling program The FCC is even allowing some AM broadcasters to using modeling to do their proofs. The better modeling programs consider ground. I can model a beverage over a salt marsh and see its diminished performance.


You are a lucky man with all those Beverages ove rocky soil!  ;D

Here are some field test results from noted MW DXer Mark Connelly, WA1ION, who compared phased loops with phased whips and something new to me, floating the feedline and intentionally using it as a separate antenna to phase against the real antenna.   This was for AM broadcast band DX-ing.

http://www.qsl.net/wa1ion/coupler/phased_spaced_antennas.htm

Maybe I'll try something today because it's raining and it is a well known fact that antennas erected in the rain work better than ones constructed during pleasant weather. 

Yep, phasing Bevs does create a monobander. That's what optimization for one band is all about - a small advantage and a give-up - no free lunches.... ;D

Though it would be easy enuff to disconnect one Bev with the coax jumper and be back to a single system for all bands. But 75M is my main band and I don't even bother.


re: Broadcash band tests for Bevs and K9AY loops: 

We find that the f-b and side rejection works more dramatically on the BC band vs: 75M.  It may be because the BC signals come in at lower angles. Both Steve and I have noticed this big performance on the BC band whereas, switching to the higher angles common to 75M, the performance was reduced somewhat.

That's not to say Bevs don't kick ass on 75M, it's just that the opportunities for lower angle incoming signals seems more domiiant on the BC band.  If we look at the vertical pattern of a Bev or K9AY, we see that the high angle discrimination is poor, whereas the low angle pattern is well defined and sharp.  A high angle view of most DX antennas looks more like an omni-directional affair.

I once put up a rotatable Adcock DFing antenna. I found on 75M, it DFed only signals that were at least 300 miles away and more. The local, high-angles signals made it useless for DFing unless it was mid-daytime when the optimum angle was much lower and liking to the Adcock vertical pattern.

T

Phased loop arrays are used by some hams with great results. They've been used in the government/military world for decades in DF operations. You can phase an array of any antenna type, so you don't need to use loops. Loops are nice in that they can be small and are relatively ground independent. And if you choose to remotely tune them, they can make a great hi-Q preselector for your receiver.

If the neighbors are OK with it  FB OM...There are stealth beverage extensions as well..I know a fellow that stapled his beverage along the wooden fence that runs the length of the alley behind his house.....and then there is the BOG (beverage on ground)   I have used a BOG before (insulated wire) with very good results...

For sure. The propagation is much more constant during the day on the BC band. It seems the angle of arrival (AO) varies little. Such is not the case on 80/75 meters at night.

There was a very good example of this during my QSO with Don - K4KYV on 3685 kHz last night. We both saw what looked like fairly major changes in the AO several times during the QSO.

He was receiving on either a Beverage or a dipole. I was receiving on either a K9AY or a dipole. At times Don was much stronger on the K9AY. Other times he was much stronger on the dipole. I saw differences of 10-20 dB. Don was seeing much the same on his end. When I was hearing him best on the K9AY, he was hearing me best on the Beverage. When he was hearing me best on his dipole, I was hearing him best on my dipole. We both used dipoles on transmit throughout.

Don is about 550-600 miles from me. The QSO was from about 9-10 PM ET. We both noted that we should set up a diversity system using both antennas simultaneously. Fading would probably be a thing of the past. :D

"using both antennas simultaneously."

That's how my Bev / quads diversity receiving system works now.

Though, a true "voting" diversity system would be neat to try too.  This would pick the strongest antenna and use it until the other took over. This is in contrast to the dual diversity system I use that keeps the two antennas on line all the time - and continuosly fed to each ear in a divided dual stereo receiver system that is sync locked.

Since the quads and Bevs are separated by more than a wavelength, I see different fading characteristics on each. When a real weak one is at the threshold, I find myslef favoring one ear or the other as the signal comes in and out. Many times I can get enuff info from the two broken up signals to put together the meaning.  Many times it makes the difference between getting the name, QTH and signal report or not. This is cuz fading on 75M can be slow, like 5 seconds at a time and much is lost in 5 seconds with one antenna.

I hear a lot of talk about "voting" systems on the HF bands, but never ran across someone using one... :-)    I know the regional police repeater systems used to use them, (and probably cell phone sites now) but have not seen a simple circuit that is easily constructed for 75M.

Though, I wonder if the brain integrating two sync'd receivers (using stereo headphones) is as good or better than a digital switch going from only A or B ?

I think the brain can be trained to be very good at integrating the two signals together vs: using just the strongest of the two - as long as the two signals are within a cycle of each other in frequency phase.

T

We be doing the Funky Electric Slide down the band, caw mawn.

I use a small, tuned receive loop so I can point the null at the local HNG (Horrendous Noise Generator).  I suppose I should take a run at the local power company instead but the loop really works well.  I'm hoping to use two, space them, point each at the HNG and try phasing them for some directivity. 

A Beverage running under a power line would be overwhelmed by noise, wouldn't it?  I could maybe squeeze in a 400' NE Beverage but I have never tried it because I supposed it would be hopelessly noisy.

A terminated Beverage is a transmission line that exhibits a velocity factor dependent upon the ground conductivity; that VF affects the tilt of the arriving wave. With a good termination it is pretty immune to coupling from other conductors, especially if crossed at 45 to 90* angles. I cross Beverages at about 2-3' spacing and have one that terminates 10' from the street power lines and another that starts at the lines. If there is noise pickup or directivity skewing I dont notice it.

Ive been considering installing a 3 el 160M wire yagi around 10' above ground aimed at the deep Southern polar regions. It should be an interesting experiment as thats a particular area that Ive found high angles to predominate when Im many hours into darkness. I spend less time on 80 but there are parallel similarities.

Carl
KM1H

 
My east/west beverage runs under a 3 phase power line at 90 degrees to the power line.....When the insulators are dusty/dirty I hear some buzz but the antenna is very usable......I had a bev than ran almost parallel to the power line and it WAS unusable...... I took it down because I never used it..


Quote-.-.-.-.-.

A Beverage running under a power line would be overwhelmed by noise, wouldn't it?  I could maybe squeeze in a 400' NE Beverage but I have never tried it because I supposed it would be hopelessly noisy.



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Posted earlier about the K9AY improving reception of some AM signals on 75 meters during the day. Attached is a good example. It is Ken-K8TV on 3875 at 2PM ET. Reception is rather noisy on the dipole (you'll hear it first) but much less so on the K9AY. Ken is about 390 miles northwest of my location.

Tom,
Voting systems are actually fairly easy to do for hams with all the receivers in 1 spot. I studied the motorola system when I worked for them. There are a couple ways to do it. First rectify the audio from each radio after filtering out the noise and send the two DC signals to a comparator. The stronger RX has its audio passed to the speaker or headphones. My Racal has another method. Ive never tried it but the hardware is in the AGC to do the voting.
Another method you need two of the same type receiver. Then take the two AGC voltages and vote on the stronger one. The Cubic R3030 receivers have both receivers driving a stereo jack so you hear 1 RX in each ear to let the brain sort it out.
Happy Snow storm

Hi Frank,

Thanks for the info. They sound like good methods. It would be pretty cool for moderate to strong signals like when working AM signals during the day.. 

The problem is when signals are near the noise floor, like when the voting system might be very useful, the noise dominates the agc (or audio) that is used for voting selection. I imagine it would become quite unstable.

I think the dual diversity system using continuous signals into stereo headphones for the brain to integrate and decide which is best is the preferred method for weaker signals. 

We were on last night working Eur and even though one antenna was louder than the other, I STILL found the info coming from the weaker antenna (in diversity) to be helpful when filling in the QSB gaps.

T
 

yes down at the noise floor could be unstable. I would think a low pass filter ahead of a rectifier would strip off some of the HF noise. I've never played with diversity except to use multiple receivers. I compare analog to SDR all the time and mercury is about eqiual. QSD, analog beats it every time. At least against the Racal AM detector.
Operating FM like the public service radios makes voting easier.

The two receiver system is superior because it uses signal from both antennas all of the time. The voting system uses only one system and thus can be throwing away useful signal at time.

Somewhere around here, I have a voting system design from the 30's. It was pretty simple and used latching relays, IIRC.

Here's another clip of the K9AY improving things on AM. Listen to the Tron on 160 meters, 26 February at about 10PM ET. The band is quite noisy and his signal isn't all that good on the dipole. Switching to the K9AY cleans it right up. On the clip, it's hard to hear when I switch the antennas (there is no audible click). Instead you will hear what sounds like Timmy fading and the static coming up. He wasn't fading. That was me switching to the dipole.

Tron is 600 miles from my location, but I saw similar results on stations as close as 250 miles.

Yep, it's definately working well on those two tapes, Steve.   Reducing the static and noise is the name of the game.

Last night when we were working Europe, there were stations that I could not hear on my low dipole at all, but 100% on the Beverage.   You were able to give these same stations good reports, so I know your K9AY and new Bev are working well - especially you being another 400 miles farther southwest than me from Eu.

T

very true Steve the brain is a lot smarter than a comparator

I know yours is. I'm not so sure about mine sometimes.   ;D

You were making me work on some of them! A few I couldn't copy. I could tell they were in there and maybe get a word now and again, but nothing substantial. I remember when you, Brent and I got on and worked some DX back around 2004 or so. There were quite a few I couldn't copy or even hear that night, so things have gotten some better on this end. Gotta be able to hear those mud ducks, KAYMOAN!!

Just buy a moonraker 6 and stop thinking so hard about all this. beverage is what you set next to the cb

Naw, just an Antron 99.   :P

Frank,

Get out your shovel!

My two beverages, the 800 footer and the two beverage 40M array (278 feet each with 90 ft spacing) both are in those big old pine trees and they seem to have little effect. 

At MOT we had voting systems to fill in dead spots for UHF police handies used in urban situations. Tac was the older system and Spectra Tac was later (late 70's). At DTC we used a 5-way voting system for microwave video and it switched on the line retrace (fast). We tried a VHF system which used two verticals spaced 1/2 lambda. It worked to fill in dead spots but in an FM system, it gave little in the way of real improvement. FM systems have good limiting and this makes up for most fades. Yes these systems simply throw away the unused (and presumed to be bad) channels.

Mike WU2D

That's why you were able to hear the Euro AMers on 3705 kHz last winter!

Mike,

I remember last year we talked about your new phased Bevs for 40M.

How well has it been working compared to your reference dipole on 40M?   Is that a switchable, terminated pair for both USA and Eur? 

T

Here's Mike working the Euros, as heard in the Netherlands.

Don't forget about the Pennant antenna, not so dependent on soil conditions and good nulls, can put it up in the air above ground and obstacles..

http://www.amatorradio.se/downloads/pennant.htm

73, Tim K8WBL

Hi Steve,

Yes the 40M Bev has been a win.

Nice recordings - I did not have a chance to listen this year as I was travelling all of January. I did manage one project last month, a Paraset transceiver. This is something that I have wanted to build for a while, and yes it works on the Beverages too. It is a cute little spy rig. works like a champ with a two tube regen and a 6V6 oscillator at 6W out!

73's Mike WU2D

That Paraset is too cool.

I hope we get quiet conditions this weekend. With the time change it might be the last good chance to work the Euro AM boys.

Some more from January 2007. Doesn't seem like it was that long ago!

I google Paraset -  Looks like a lot of these have been reproduced.

Yes the set has a following that started in Europe a few years ago and quite a few people have been making them and using them on the air.

The Italians got things started, then the Scandanavians and then the Brits and pretty soon hams all over were building them. Hey a three tube XCVR with historical significance, using common parts that really works is a good club project.

http://www.qsl.net/ik0moz/paraset_eng.htm

Mike WU2D

Very nice. But I guess you can only use it in the deep woods or in an attic during the dead of night.   ;)

1) Anyone using 75 ohm flooded CATV cable to their receive antennas?  It's what DX Engineering is advocating these days. The RG-62A to my receive loop #1 is old and looking rough. I'm pondering this as replacement. The F connectors look clever too since I already have them and the tool but I would have to change my world.

2) Anyone using a small K9AY?  The one I find when I Google (I've lost the original article) is a 160/75.  For just 75 maybe I could shrink it.

3) Could you guys move?  I've been experimenting with phased small receive loops.  I point each at the local HNG (horrendous noise generator) to null that out then fool with the phasing to listen east.  I tune in one of you jokers, turn on the product detector, fiddle with phase and gain until your carrier is nulled then flip the phase.  S/N on your signal goes up but it's not dramatic. I'm beginning to think that all the darned noise on the band is over the US of A and that cutting out the noise from the Pacific isn't doing me much good.  So how about moving to Hawaii? The weather is better.

Ca is a weird place. Such a big state but people are packed in like chickens with tiny yards. It always reminded of a study done on rats confined to small spaces. Maybe you should move this side of the big hill.

Yes, works great. I bury mine. Protects it from the lawn mower and reduces common mode current noise.

Steve,

I've never used the stuff.  Can you solder regular PL-259/UG176's to it or is it better to go with the F connectors and adapters where I have to?

Indeed it is. We used to think of it as two states, north and south jammed together but it's really east/west.  The eastern part of the state is agricultural.  CA is the biggest ag state in the country.  The coast is crowded in different ways near SF and LA.

I have 1/3 acre acre in Silicon Valley which is huge by CA suburban standards but it's crummy from an antenna perspective, a triangle with a power line along the base.  The hypotenuse gets the dipole, the short side the receiving loops and the base gets nothing.  The redwood trees are in the wrong places too.

Instead of moving to your side of the hill, how about stopping right on top?  That seems interesting if cold.

I have been using some nice Belden RG-6 for the Bevs that I scrounged - it is really low loss stuff.

Mike WU2D

Jon:

I never tried to put a PL-259 on the stuff. The snap F connectors were just too easy. I would imagine you could put any appropriately sized connector on that coax.

Mini-8 reducers (the numbers escape me ATM) work great.

--Shane

UG-176

When I frst put up the Beverages I ran 700' of RG-6 flooded quad shield on the ground. It lasted about 5 months before the critters destroyed it in several places allowing water to get in.

Ive been using 1/2" CATV hardline for the past 18 years and no more problems. The hardline goes to the remote relay box and the Beverages are fed with ~10' runs of that RG-6 as that group all start at the same tree.

Carl
KM1H